LAUSR

Abstract We report numerical investigation of mid-infrared supercontinuum (SC) generation in all-normal dispersion (ANDi) As39Se61 chalcogenide photonic crystal fiber (PCF). Numerical results, obtained by using the Finite-Difference Frequency-Domain (FDFD) method, indicate that desirable dispersion properties can be achieved by adjusting the air holes diameter and ANDi regime is obtained over the entire wavelength range with a PCF pitch and air holes diameter of 1.8 µm and 0.7 µm, respectively. Besides, the optimized design has a nearly zero dispersion wavelength of 3.45 µm and exhibits high Kerr nonlinearity of 5.89 w−1 m−1. By pumping 50 fs duration laser pulses at 3.45 µm, we demonstrate the generation of a broad, ultraflat-top and highly coherent SC spectrum extending from 2.43 µm to 4.85 µm at 4 dB spectral flatness and from 1.95 µm to 6.58 µm at 8 dB, by employing very low energy pulses of 50 pJ and 250 pJ, respectively. Owing to its remarkable optical characteristics, the proposed SC source based on As39Se61 chalcogenide glass PCF is found to be suitable for various potential mid-infrared applications such as optical coherence tomography, mid-infrared spectroscopy and metrology.